WO2016034660A1 - Ergonomic schoolbag device for children or adolescents, and backpack for adults - Google Patents

Abstract

The invention proposes a backpack schoolbag for children having lateral shoulder straps. It comprises one or more waist belts made of elastic material. It is anchored to the main body at at least two anchoring points that are separated by at least a quarter of the height of the schoolbag. Such "intertwining" makes it possible to carry the recommended loads while dispensing with the shoulder straps, and therefore reduces the loading on the upper vertebral column. The main body includes a front compartment adjacent to the bottom and to the back panel. This compartment forms a rectangular parallelepipiped having a thickness less than its height and width, for holding books and/or files. Optionally, the schoolbag comprises complementary compartments behind and/or above said front compartment. This complementary compartment has dimensions not suitable for holding a book or file. Optionally, the schoolbag has a dynamometric handle providing a visible measurement of the load. Optionally, it comprises a removable compartment in front of the wearer.

Description

 "Ergonomic school bag device for children or teenagers, and backpack for adults"

The invention provides a backpack, more particularly adapted to the growth of the child and the physiology of the spine, comprising a "envelope with side straps". According to the invention, this binder further comprises at least one ventral holding belt which is made of an elastic material, in order to press the contents against the back regardless of its filling. This lap belt is anchored on each side of the envelope, behind the compartment containing the school affairs in at least two "ventral" anchoring points located posterolaterally and separated by a holding height of at least one quarter of the height of the binder, or even the third or half.

 According to another feature of the invention, the envelope includes at least one inner wall defining at least one anterior or main compartment which is adjacent to the lower bottom and the back panel of said casing. Such a compartment is arranged to have a rectangular parallelepiped shape of a thickness less than its height and width, and of determined dimensions to accommodate one or more books, binders and / or notebooks. Preferably, the binder comprises one or more complementary compartments located behind and / or above said front compartment. According to this feature, such a complementary compartment has dimensions determined to not be able to accommodate a book or a binder, or even a notebook or a binder.

According to yet another particularity, the binder comprises a grip handle provided with a dynamometric device arranged to provide a visible measure of the weight of the binder. Optionally, the briefcase further comprises an additional independent compartment that is removably attached to the shoulder straps and / or the waist strap on the front of the wearer. State of the art

The invention relates to the field of school bags, ie luggage designed and made specifically to allow more particularly children and adolescents to carry books and / or notebooks and / or binders necessary for their outward journey and / or return between the home and school (that is to say, about 10 years old) or college (that is, until about 15 years old) _^ In France and in many countries, the organization of work and programs Education is based on the use of classbooks and / or notebooks, and recently digital tablets and weight computers that may be important. In many cases, students must use these books and notebooks both in the school where the classes are held, and at home to study or do additional work.

 But books and notebooks, stacks of sheets of paper or cardboard, are rather heavy objects in relation to their volume. Transporting several to each trip is a significant weight, especially for schools where several different courses take place on the same day, and therefore where you have to carry several books and several notebooks, typically at least one per course. A schoolbag, according to its age and its course of the day, can often weigh between 5kg and 10kg, see more.

 For a long time, there are schoolbags in the form of a semi-rigid rectangular bag well adapted to the shape of the books, and provided with two straps to carry the bag as a backpack hiking. However, the weight distribution on both shoulders and the adjustment of the straps are insufficient given the excessive weight transported. In addition, the behavior of the child during his movements, run or jump for example, significantly increases the effect of this load on its musculoskeletal structure.

For example in France, the circular of January 2008 of the Minister of National Education, indicates that the weight of school bags is a public health problem. It states that it should not exceed 10% of the body weight of children, and therefore be reduced by 50% compared to current habits. Indeed, the physiological data of the development of the child tell us that:

 - The vertebrae of the child are ossified only at the age of 14 years for girls and 15 years for boys.

 - The intervertebral discs are harder than the cartilages of

 vertebrae growth.

 - Thus, scientific studies clearly show the impact of the

 weight on deformation of discs and spine growing; and in particular, the existence in 50% of adolescents of pre-lesions that will prove to be true herniated discs in adulthood.

Unfortunately, it turns out that 80% of children in elementary schools and colleges wear satchels too heavy, since the average weight transported each day exceeds 20% of the weight of their body.

 Thus, there is a real public health interest to change this situation.

Numerous studies and attempts have been made in this direction, on the one hand by trying to limit the amount of books that students need to carry, or think they have to carry. However, in the case of a wide variety of factors involving many stakeholders on a daily basis, improvements are difficult to implement and impose, and therefore often temporary and generally insufficient.

In this context, the design of binders is therefore a delicate and relevant issue. Briefcases used by professionals are not intended to be worn on the back, and rarely for more than ten minutes in a row. For their part, even though hiking backpacks are sometimes very technical and highly studied products, their design does not correspond to the context of use by a growing child and various school uses. For example, they are intended to carry mainly clothing, while satchels must carry heavy and rigid books and notebooks. The best-studied backpacks are designed for long, but quiet, multi-hour trips by adults. On the contrary, schoolbag is only used for one hour at most, but by a child whose growth is not over and whose behavior is much more agitated and unpredictable.

 Thus, the school bag for children or teenagers is a particular area with specific constraints. In this use, these other products are not usable satisfactorily, and their technologies are often irrelevant. Although personal tastes and fashions make the use of various bags such as shoulder bags or small backpacks, and other bags such as handbags, widely used, these products are often chosen by Older users are not selected based on the actual needs of the school context or based on knowledge of physiology for health. Similarly, the musculature of adults working all day long is not sufficiently prepared to carry a heavy load.

 An object of the invention is to overcome all or part of the disadvantages of existing binders, and to help reduce the stress on the spine by the schoolbag of a child or teenager, or the bag on an adult's back in his regular use. Presentation of the invention

 The invention provides a backpack for children, comprising a flexible or semi-rigid envelope comprising an anterior dorsal panel, and which is reclosable around a storage volume. This binder is of a type provided with at least two side straps each fixed to an upper anchorage point at the top and a lower anchorage point at the bottom of said envelope, for carrying said binder.

According to the invention, this binder further comprises at least one ventral holding belt which is made of an elastic material, for example more than 20% elongation before deterioration or rupture, and for example between 5% and 20% of stretching for a traction equivalent to twice the maximum weight of the schoolbag, for example for a maximum weight between 3kg and 6kg. This ventral holding belt is anchored on each side of the envelope in at least two points "anchor ventral" said upper and lower, which are separated by a height called maintaining at least a quarter of the height of the binder, for example the height of the storage space or the height between the bottom of the storage volume and the upper anchorage points of the straps. Preferably, this holding height is at least one third to one half of the height of the binder. According to the embodiments, the ventral anchor points may include the lower strap anchor points. These anchor points are here called "ventral" anchoring because they serve to anchor the ventral support belt. As understood, however, they have a position that can be described as posterolateral with respect to the body of the wearer.

 The briefcase according to the invention thus allows a real "interlacement" of the storage volume and its application in permanent contact with the back of the wearer. A reduction of the lever arm exerted by the weight of the schoolbag is obtained, the impacts are reduced, and the friction better participate in the support of the load.

 Thus, even with respect to the ventral strap specialized backpacks for hiking, which are nevertheless a different technical field and clearly target an adult clientele and fully developed and prepared for the effort on the musculoskeletal level, the binder according to the invention brings a contact on a region much more distributed and more stable than on the narrow or even linear band which is applied by the unique anchoring of the ventral straps existing on such specialized bags.

 In addition, the experimentation by the inventors of the wearing of such a binder by "embracing" has highlighted the fact that it is even possible to support the recommended weights (10% of the body weight) by removing the straps on the shoulders, that is to say only with the elastic belt. This is an important indication that the invention considerably reduces the load generally exerted on the upper part of the spine through the shoulder straps, even if these remain of practical and dynamic interest.

The features of the invention apply to specialized luggage for the transport of school loads by children. They also apply for carrying luggage of different types of loads by adults, for example with some heavy and bulky loads handled similarly to books or notebooks, such as a laptop.

 For children or adolescents as for adults, the advantages of the invention allow such a load port to be better adapted to the current evolution of the individuals and to the recent evolutions of the body diagram, which are modified and weakened of the increased sitting time, especially at work, which weakens the spine.

 Indeed, recent scientific studies show that prolonged sitting posture disrupts the body's recovery regimen and causes loss of vigilance in the back muscles. Faced with these new uses of life and work, including the widespread use of computers that condition immobility, excess load carrying becomes a Public Health problem increasingly serious.

 Different features of the invention are here listed, which can be combined with each other.

 According to a feature of the invention, at least one ventral retaining belt, called posterior, is anchored to the casing at ventral anchoring points located on a panel forming a posterior wall of said envelope or a compartment within of said envelope.

 The traction of this posterior belt thus applies directly to this posterior wall. Its action is thus pressed against the back of the wearer not only the back panel of the envelope but also the contents of this envelope, or compartment concerned. For example, the pressure on the contents of the envelope or compartment creates a compaction of this content which gives it a greater stability of shape and behavior, for example by the support of the books against each other which prevents them to slide on one another.

According to another feature of the invention, the envelope includes at least one inner or outer wall defining at least one front compartment which is adjacent to the bottom bottom and the back panel of said casing, for example a single compartment in a single volume, or several compartments juxtaposed with each other one behind the other or one next to the other and adjacent to the back panel. Such a compartment is arranged to have a rectangular parallelepiped shape of a thickness less than its height and width, and of determined dimensions to accommodate one or more books and / or notebooks.

 The user is thus encouraged to arrange the books and notebooks, which are usually the heaviest items in a schoolboy's binder, in the compartment that is closest to the back panel, and therefore where they will be best stabilized and create the weakest lever. Preferably, this compartment is located in front of a posterior ventral support belt, which therefore specifically plating the heavier elements.

 More particularly, the anterior compartment preferably has a thickness determined to be able to receive a limited thickness of books and / or notebooks, which thickness is calculated to represent a maximum weight determined.

 It is thus impossible or difficult for the user to store in the binder more books or notebooks than the thickness of this previous compartment allows. Books and notebooks are generally the most dense elements in a binder, so the total weight of the binder is limited to an approximate value that depends directly on the number of books and notebooks, for example, depending on the density of the books and / or or notebooks for which it is intended. This maximum weight value that can be contained in the binder can thus be adjusted by these dimensions, for example according to the age or weight of the user.

 According to yet another particularity of the invention, the envelope comprises a dynamometric device arranged to provide a visible measurement of the weight of the schoolbag when said schoolbag is raised or suspended by a gripping handle at the top. In some embodiments, the handle is formed by or attached to one or both side straps.

The holder of the binder, but also the other persons who surround him and / or have it under his responsibility, can easily know the total weight of the binder, even without or against the will of the wearer. In addition to improving the carrying of the schoolbag and limiting the weight it contains, the invention thus makes it possible to make more visible the problem posed by excessive weight, which is already recognized by the Ministry of National Education. The invention thus makes this problem more difficult to hide or dodge, and thus allows a better awareness of all.

 Another feature of the invention is provided, wherein the binder further comprises an additional compartment, for example in the form of a pocket, which is independent of the envelope of said binder and is attached to the straps and / or the ventral waist belt, on the front of the wearer, by detachable fastening means fast maneuvering.

 This additional pocket thus allows the user to easily carry additional objects that could not enter the main envelope. It is a kind of planned overcoming of the expected weight, which allows a certain flexibility in the carried weight without losing sight of the reality of this overtaking. This overrun is located in front of the body, which makes it clearly visible to the user, since he realizes that it is necessary for him to use the additional compartment. It is also visible to those around it, for example parents or teachers. The position of this overhand pouch on the front of the body also balances the overload on the wearer.

This front cover allows to have better access to its content than the binder when on the back. In practice, this option facilitates access to documents and extra-curricular objects (transport card, notebook, notebook and other objects of frequent access) while allowing the maintenance of the port by embracing since these objects are thus accessible without access the main bag. This prevents the child from wearing his bag on one shoulder while using these objects and before putting them back. In addition, the position of this content at the front of the wearer allows a better load distribution between the front and the back of the wearer and thus to balance the muscular efforts. Optionally according to the embodiments, similar to the compartments of the main envelope, this additional compartment is made with dimensions that prevent the insertion of books or notebooks, or on the contrary dimensions that allow it but in a quantity determined by a maximum permissible weight.

 Thus, the invention makes it possible in particular to reduce the stresses exerted on the spine for a given load and thus to wear it more efficiently and less damaging to its current and especially future health, in the specific context of a school bag. characterized by its type of charge and the type of use that is made of it. It also makes it easier to limit the load borne by the child. These elements bring in other elements public health insofar as these means participate in the prevention and the fight against back pain of the young adult.

 Various embodiments of the invention are provided, integrating, according to all of their possible combinations, the various optional features set forth herein.

List of Figures

 Other features and advantages of the invention will emerge from the detailed description of an embodiment which is in no way limitative, and the appended drawings in which:

 FIG. 1 is a side view diagram illustrating part of the forces applied to a schoolbag according to the invention;

 - FIGURE 2 is a perspective diagram from the front, which illustrates an exemplary embodiment of the invention with independent side straps of the ventral waistband;

 FIGURE 3 is a diagram from the rear which illustrates the operation of the torque handle in an exemplary embodiment of the invention;

- FIGURE 4 is a rear perspective diagram, which illustrates an exemplary embodiment of the invention with side straps independent of the ventral waistband, for example the one of FIGURE 2, comprising a single dorsal compartment and an upper complementary compartment;

 FIGURE 5 is a side diagram illustrating an exemplary embodiment of the invention with independent side straps of the ventral waistband, comprising a two-part dorsal compartment and an upper complementary compartment;

 FIGURE 6 is a front perspective diagram illustrating an exemplary embodiment of the invention with removable upper side straps clinging to both portions of the ventral waistband;

 FIGURE 7 is a perspective diagram from the back of the binder of FIGURE 6;

 FIGURE 8 is a front diagram, which illustrates an exemplary embodiment of the invention with fixed upper side straps clinging to the two parts of the ventral waistband;

 FIGURE 9 is a front diagram, which illustrates an exemplary embodiment of the invention with upper side straps secured together and carrying the torque handle, and clinging to the fastening buckle of the two parts of the lap belt. holding, which is made and anchored discontinuously but distributed;

 FIG. 10 is a front perspective diagram illustrating an embodiment of the invention, for example that of FIG. 6, in a variant with an additional compartment.

Description of an exemplary embodiment

 FIG. 1 diagrammatically illustrates a number of forces involved in carrying the briefcase according to the invention, in an exemplary embodiment with side straps independent of the ventral waistband, which is illustrated in FIG. 2.

The explanations presented here for this exemplary embodiment are also valid for the other embodiments presented below, which shares the same main features and benefits.

 The weight of the schoolbag being generally suspended on one or both shoulders, moments of forces proportional to the weight PI and the lever arm D3 are exerted at different levels of the spine.

 This lever arm is the horizontal distance D3 which separates the center of gravity G1 from the bag 1 and the bearing point G3 of the main reaction force R3 of the spine 90. The more the weight is moved away from the column, the more the moments strengths are important. In addition, to balance the moment of force of the load, the child must lean forward to use muscles that do not participate in the straightening of the back; which has the effect of increasing or even doubling this load by a horizontal component R31 and to work the body in a posture that is even less effective and healthy.

 Under the effect of these increased and poorly positioned loads, the muscles get tired quickly, and the load port becomes "PASSIVE". It is then supported directly by the skeleton, instead of being dynamically managed by the muscles. In addition to the muscle pain caused by the contractures, the constraints are localized according to its morphological type, and this location of constraints constitutes areas of overwork with age. That is to say, it can aggravate the initial weaknesses of this conformation and be the source of pre-lesions that will become chronic lesions for the whole life.

It is useful to remember that in prolonged sitting position, movements of the pelvis and spine around the balance contribute to the maintenance of the neuromuscular regimen of recovery and the vigilance of the deep muscles, which are useful for carrying loads. . Given the duration of the child's sitting position (4000 hours / year) due to new uses of life and work, and the bad postures frequently adopted because of habits acquired and the lack of ergonomic furniture, this neuromuscular schema is already particularly proven and unsuited to carrying loads during his travels. interlacing

 In briefcase 1 according to the innovation of the invention of the charging port by embracing, the elasticity with a significant elongation provided by this ventral support belt 3, possibly with an adjustable length adjustment, allows this belt 3 of be in permanent tension t3, without disturbing the wearer 9, despite the shocks or jolts caused by the movements of the wearer, even abrupt and important. This permanent tension is thus applied to the envelope 10 of the binder, which keeps it in constant contact with the back 91 of the wearer 9.

 The shocks between the back and the binder are removed or decreased, and the distance between the center of gravity of the binder and the axis of the spine 90 of the wearer is kept permanently at a minimum, and therefore the lever arm D3 to which applies the PI weight of the binder.

 The vertical extent h3 on which this belt 3 is anchored to the schoolbag allows this maintenance in contact is carried out regularly on a two-dimensional contact surface c91 back 91 representing a high height h91. This support height allows for better friction so less slippage along the back. The support against this dorsal contact surface c91 thus allows a reaction force RI which balances a portion of the weight PI of the schoolbag, furthermore applied with a lower lever arm D1 than the one D3 applied to the reaction R3 supported by the braces. 2 resting on the wearer's shoulders.

 Simultaneously, this belt 3 prevents or limits the rotation of the load backwards, thereby reducing, for example, jerks and backward forces applied to the shoulders of the wearer and which require an effort R31 forwards.

 Thus, even with respect to specialized backpacks for hiking, which are nevertheless of a different technical field and clearly target an adult clientele and fully developed musculoskeletal, the briefcase according to the invention provides a contact on a a region much more distributed and more stable than on the narrow or even linear band which is applied by the unique anchoring of the ventral straps existing on such specialized bags.

In addition, as shown in FIGURE 1 and FIGURE 5 for binders 1, la and preferably in all embodiments, the back panel 11 has a thickness El i not regular over its height, or includes such an insert or is attached to such an element, which can be more or less rigid or elastically deformable. The vertical profile of this panel or dorsal insert is determined to be complementary to the back profile 91 of the wearer, preferably with at least one complementary convexity of the lumbar lordosis 92.

 This form thus provides a lumbar wedging which facilitates the application of a continuous support on a large height of the back, and at the same time allows a wide contact c92 between the binder and the sacro-lumbar region 92 of the wearer, typically in the part low lumbar lordosis. This contact c92 increases the friction force RI mentioned above, but also allows this part of the body to support a portion R2 of the vertical component generated by the weight of the bag, and with a lever arm D2 even smaller. The efforts R3 and R31 applied to the shoulders and therefore the spine are further reduced.

 Preferably, the back panel 11 is made in its entirety in one or more flexible materials, that is to say that it has no rigid shell or reinforcement which is sufficiently high to maintain its vertical geometry or its contact profile with the back of the user. More particularly, the rest of the schoolbag also does not include such a rigid shell or frame, or at least not in the front half of its structure.

 Also preferably, alternatively or in combination, the back panel 11 includes one or more inserts whose shape and thickness determine the thickness El i, made of one or more elastic foam type materials, with closed cells and / or open . Preferably the panel has a fully elastic behavior in its thickness, without inclusion of purely viscous gel insert. The foam used preferably has a low stiffness, for example a Shore A hardness less than 15 and in particular a Shore 00 hardness between 5 and 30.

Optionally, the back panel 11 is rigidly or resiliently connected to a rigid support member 121, firmly enough to allow the schoolbag to remain stable when it is "standing" on this support element 121. For example but not necessarily, this support element is made by a plate inserted into the bottom 12 of the envelope, or integral with this bottom on its underside.

 As illustrated in FIG. 5, this support 121 is for example formed by a rigid plastic part, mainly horizontal but of which a part of decreasing thickness rises and integrates integrally into the bottom of the back panel 11.

 By using such a rigid but low-height support H121 relative to the back panel to which it is attached (for example less than 30% or even less than 20%), a support functionality is obtained without compromising the adaptability advantages. provided by the flexibility and elasticity characteristics of the back panel.

FIGURE 1 to FIGURE 2, FIGURE 4 to FIGURE 7, and FIGURE 10 illustrate a preferred but not mandatory feature that can be implemented in all embodiments.

 According to this feature, the binder 1, the to the according to the invention comprises at least one ventral belt 2, 21, 22, said rear, which is anchored on the casing 10 at the ventral anchor points 321, 322 , 331, 332 located on a panel forming a rear wall 13 of said casing as illustrated in the figures cited, or a rear wall of a compartment within said casing.

The traction t3 of this posterior belt 3 thus applies directly to this posterior wall, and its action comes to press against the back of the wearer not only the back panel of the envelope but also the contents of this envelope, or at least the compartment concerned. For example, the pressure on the contents of the envelope or compartment creates a compaction of this content which gives it a greater stability of shape and behavior, for example by the support of the books against each other which prevents them to slide on one another. Optionally but not mandatory, which can be combined with the other features described here, the schoolbag according to the invention comprises several ventral support belts.

 Thus, in the exemplary embodiment illustrated in FIGURE 5, the binder further comprises a second ventral holding belt 4, said anterior, which is anchored on a panel 14 located in front of the anchoring panel 13 on which is anchored the posterior ventral belt 31, 32.

 In this example the second belt 4 can also be described as a posterior belt since it is anchored to an inner wall 14 which forms the rear of the front compartment 101 the foremost. This is therefore a belt of "posterior" nature, but which forms an "anterior" belt relative to the posterior belt 3 which is anchored behind it.

 Alternatively, and not shown here, this anterior belt is anchored simply on the dorsal panel of the envelope, or preferably on the back of the anatomical backrest 11 if it exists.

 The traction of this anterior belt 4 will press this back panel permanently against the back of the wearer, which improves comfort and limits slippage between the two.

 The load restraint provided by the posterior belt is particularly improved by the presence of an additional front belt, for example because the different compartments 101, 102 are each individually maintained. The vertical movements between two compartments are limited, tension adjustment is easier and more independent, and the back panel stays in better contact with the back.

 Possibly, this (these) belt (s) can be anchored (s) discontinuously or even punctual, for example in only two anchor points.

Preferably, however, as in the exemplary embodiments presented herein, the belt (s) 3, 31, 32 are anchored to the binder 1, la, lb, le, le, and b, between the two dots. upper ventral anchor 321, 331 and lower 322, respectively 332. Alternatively, a semi-continuous anchoring is carried out, for example as illustrated in FIG. 9, on a plurality of points or portions of ventral anchoring forming one or more regions whose cumulative height h39 represents at least 30% or even 50% of the distance h3 separating said two upper and lower ventral anchor points.

 The traction of this ventral support belt thus applies regularly over the entire height h3. The contact c91, c92 with the back is reinforced, and the maintenance of the load more regular and more reliable, for example when the transported objects rise less high than the upper ventral anchor point 311, 321.

 Preferably, but not necessarily, ventral waistband 3, 4 has in its part on the front of the wearer a height h3 of at least 10 cm, or even at least 15 cm.

 Load optimization

 In FIGURE 4 is illustrated a preferred but not mandatory feature that can be implemented in all embodiments.

 According to this feature, the envelope 10 of the binder 1, lb comprises several compartments.

 On the one hand, one 101 of these compartments is said to be anterior because it is located adjacent to the back panel 11, ie as far forward as possible of the binder. It is also preferably situated at the bottom of the volume enclosed by the envelope, for example adjacent to the lower panel 12. In the present example, this anterior compartment 101 is delimited by the bottom 12 and the rear 13 of the envelope, and only by the side walls and a ceiling 15.

 This front compartment 101, or main, has width dimensions L101, L104 and height H 101, H104 which are determined to accommodate one or more books or notebook 81.

On the other hand, the binder comprises one or more complementary compartments located behind and / or above said front compartment. In the present example, the binder 1 comprises a complementary compartment 103 which is situated above the anterior compartment 101 from which it is separated by the horizontal inner wall 15. According to this characteristic, such a complementary compartment has specific dimensions, here through its height H103 and its thickness E103, to not be able to accommodate a book or a binder, or even a notebook or a binder (for example to be able to accept a small binder or notebook but not a big one).

 FIG. 5 shows an exemplary embodiment in which the binder also has such an "anterior" compartment which is formed by two volumes 101 and 102 separated by an inner wall 14. These two compartments are both located at the bottom of the envelope and closed downwards by the bottom 12, and their set is well adjacent to the anatomical bottom 11. Their height hlOl and their width are provided to be able to receive books and notebooks 81.

 Optionally, the volume 101 at the front of the main compartment is sized to accommodate larger objects, for example books or large binders (for example in A4 format), while the volume 102 is the largest. The rear is dimensioned to accommodate books, notebooks or binders of smaller size (for example in the format 17x22cm), giving it a height lower than that hlOl volume before 101.

 As in the example of FIGURE 4, they are surmounted by a "complementary" compartment 103, the combined dimensions of height h103 and el03 do not allow to accommodate books, but only objects 82 of smaller dimensions.

 Books and notebooks are usually the heaviest objects that are typically carried by a schoolboy. Now they all have a flat shape whose two external dimensions are both important, and are difficult or impossible to bend or roll, in any case without visibly damaging them.

Such complementary compartments 103 are for example designed so as not to have more than one dimension L103 which exceeds that of a book or a standard notebook. They can thus accommodate many objects such as a pencil case or various accessories 82, but the user can not carry books or notebooks. Thus, while allowing to carry books and notebooks in the compartment most suitable for the health of the wearer, such a binder also offers an additional volume that can transport other varied objects, but it is difficult or impossible to use to add other books or notebooks that could load the binder significantly beyond a maximum weight chosen at conception

 For example, standardized formats of books, or sheets or notebook are for example 21x29, 7cm for a sheet of A4 or a large notebook, 17x22cm for notebooks of smaller size, and similar dimensions for books of class.

 The previous compartment or compartments intended for them may thus have dimensions of the order of 25 × 40 cm in width and height to accommodate these formats vertically, and a thickness of the order of 10 cm to 25 cm to receive the maximum number of these corresponding formats. the maximum weight chosen for the binder.

 Other potentially transported objects have many different and unpredictable dimensions. However, they generally have a substantially lower overall density than paper, and are less likely to accumulate beyond a certain amount.

 For example, the complementary compartment or compartments each have only one dimension that exceeds 15cm, and may for example have a cylindrical or rectangular shape of the order of 10x10x25cm, or 15x15x20cm, or 5x15x30cm.

 For example, the "previous" compartment or compartments, the only ones that can accommodate books and notebooks, are sized so that the total foreseeable weight of the binder does not exceed the limits recommended by the French Education Circular, namely:

- 10% of the average weight of a child in elementary school, ie 10% x 25 kg = 2.5 kg

- 10% of the average weight of a child in college, 10% x 40 kg = 4 kg.

In FIGURE 10 is illustrated an optional feature that can be implemented in all embodiments. According to this feature, the binder also includes an additional pocket 6 independent of the envelope 10 of said binder and which is attached to the shoulder straps 21, 22 and / or the ventral holding belt 3, 31, 32, on the front of the carrier 9, by detachable fast-acting fastening means 61.

 Optionally, the binder includes several additional pockets that can be hung together visibly. Alternatively, there are several pockets of different sizes and having a different color or shape, and only one at a time can be attached to the binder.

 This feature allows users to have additional storage space in addition to that of the main envelope 10. It allows them to reduce the constraints imposed by such physiological standards, so do not discourage them in the use of binder according to the invention, while still providing them with other ergonomic benefits it allows.

 Torque handle

 In FIGURE 3 is illustrated an exemplary embodiment of a dynamometric device as provided preferably in the binder of the invention.

 In this example, the dynamometer device comprises an elastic member 51, for example an elastic textile for a metal spring, which is attached to the grip 5 and then extends downwardly through a partially formed sliding aperture 53 high of the envelope 10, here at the top of the dorsal anterior panel 11. This elastic element 51 slides in a sliding space, here a sleeve inside the back panel 11, and is attached to said envelope at a point of anchor 54 located lower than said sliding opening.

 This elastic element 51 carries a plurality of distinct marks 55a to 55e each corresponding to a determined weight Pla to Pie of the schoolbag 1, for example marked by numbers or letters, or preferably by colors ranging for example from green to weight the lightest Pla to red for the heaviest Pie.

Each of these marks is on the elastic element in a position determined to be visible above the holding opening, under the effect of an elongation of the elastic element 51 caused by the weight of the binder when lifted by said handle 5, if and only if the weight of the binder exceeds the weight Pic corresponding to said mark 55c. The elastic element is for example slidably included in the thickness of the back panel. For example also, the elastic member is similarly included within one or both straps.

 Alternatively, the marks are arranged on an element which is displaced with respect to a fixed element under the effect of the elongation of the elastic element 51.

 In a variant illustrated in FIG. 9, the dynamometric gripping handle 5 is fixed to the end of the upper left and right half braces 22. These are fastened together on a part which is hooked by quick coupling with the belt, here with the buckle 33 of quick attachment of the two half-belts 21 and 22.

 In this example, the torque handle 5 is attached to two elastic members 51 which each slide in a lateral half-strap, and protrude by a length varying according to the force applied to the handle. In this example, the straps themselves are not elastic and do not participate in the dynamometric measuring chain. The handle can be used for example to hang the bag at a hook, when the shoulder straps are detached from the buckle 33 belt.

 Alternatively, the dynamometric device includes the shoulder straps, and thus allows to know in real time applied to the straps on the shoulders of the wearer.

 According to a variant illustrated in FIG. 7, the dynamometric device is formed by an electronic sensor, the result of which is displayed in a known manner, for example by a screen 59.

 Example of various variants

 Preferably, in the binder 1, according to the invention the at least one ventral holding belt 3 is formed in two half-belts 31, 32 joined at the belly of the carrier 9 by releasable attachment means to fast maneuver 33.

The binder 1, the embodiments illustrated in FIGURE 1 to FIGURE 5 is made with side straps 21, 22 independent of the one or more ventral support belts 3, 4, which allows, for example, separate adjustments.

 Alternatively, FIGURE 6, FIGURE 7, FIGURE 8 and FIGURE 10 illustrate a preferred but not mandatory feature, which can be combined with the other features herein set forth. According to this characteristic, each half-belt 31, 32 of the binder lb is also fixed, on the side of the ventral attachment 33, to the side strap 21, respectively 22 corresponding thereto.

 In such a situation, it can thus be considered that the lower anchorage of the side straps 21, 22 is formed by the anchoring points 311 to 312, respectively 321 to 322 of the lowest holding belt 3, 31, 32. .

 More particularly, the side straps 21, 22 of the Satchel lb are fixed on the half-belts 31, 32 respectively by detachable fast-acting fastening means 213, 223.

 Of course, the invention is not limited to the examples that have just been described and many adjustments can be made to these examples without departing from the scope of the invention.

Claims

1. Satchel (1, la) or backpack for child, teenager or adult, of the type comprising a flexible or semi-rigid envelope (10) comprising a dorsal anterior panel (11), and which is reclosable around a storage space and provided with at least two lateral straps (21, 22) each fixed to an upper anchorage point (211, 221) in the upper part and to a lower anchor point (221, 222) in the lower part of said envelope, for carrying said binder on the back, characterized in that it further comprises at least one ventral holding belt (3, 31, 32) which is made of an elastic material and is anchored on each side of the casing in at least two belly anchor points said upper (321) and lower (322), which are separated by a so-called holding height (h3) of at least one quarter of the height (hl) of the binder, and in particular at least one third of this height. 2. Schoolbag (1, la, lb, le, le) according to the preceding claim, characterized in that the at least one ventral holding belt (3, 31, 32) is anchored to the casing (10) continuously between the two upper (321, 331) and lower (322, respectively 332) ventral anchoring points, or on a plurality of ventral anchoring points forming one or more regions whose cumulative height represents at least 30% or even 50% the distance (h3) between said two upper and lower ventral anchor points. 3. Satchels (1, the to) according to any one of the preceding claims, characterized in that the ventral holding belt has in its portion on the front of the wearer a height (h3) of at least 10cm, or at least 15cm. 4. Satchel (1, la) according to any one of the preceding claims, characterized in that the back panel (11) has a thickness (El i) not regular over its height, the vertical profile is determined to be complementary to the back profile (91) of the wearer, preferably with at least one complementary convexity of the lumbar lordosis (92). 5. schoolbag (1, la) according to any one of the preceding claims, characterized in that at least one ventral belt, said posterior, is anchored to the casing (10) at anchor points ventral (321, 322, 331, 332) located on a panel forming a posterior wall (13) of said envelope or a rear wall (14) of a compartment (101) within said envelope. 6. Satchel (la) according to the preceding claim, characterized in that it further comprises at least a second ventral sash (4), said anterior, which is anchored to a panel (14) located in front of the panel ( 13) anchoring the posterior ventral belt (31, 32) 7. schoolbag (1, la) according to any one of the preceding claims, characterized in that the casing (10) comprises a dynamometric device arranged to provide a visible measure of the weight of the schoolbag when said binder is raised by a handle (5) located in the upper part. 8. Satchel (1, ld) according to the preceding claim, characterized in that the dynamometric device comprises a resilient element (51) which is fixed to the handle (5) and then extends through a sliding opening ( 53) formed in the upper part of the envelope (10) and is fixed to said envelope in at least one anchoring point (54) situated lower than said sliding opening, said elastic member carrying or displacing one or more marks (55a to 55e) each corresponding to a determined weight (Pla à Pie) of the schoolbag (1), each of said marks being disposed on or in relation to the elastic member at a position determined to be visible above the holding opening, under the effect of an elongation of the elastic element (51) caused by the weight of the bag when lifted by said handle (5), if and only if the weight of the schoolbag exceeds the weight (Pic) corresponding to said mark (55c). 9. Satchel (1, la) according to any one of the preceding claims, characterized in that the casing (10) includes at least one inner wall (14) or outer (13) defining a single or multiple compartment said anterior (101, respectively 104) which is adjacent to the bottom bottom (12) and the back panel (11) of said casing, and is arranged to have a rectangular parallelepiped shape of a thickness (E101, E102, E104) lower than its height (H101, H 104) and its width (L104), and of dimensions determined to accommodate one or more books and / or notebooks. 10. Satchel (1, la) according to the preceding claim, characterized in that the front compartment (101, 102, 104) has a thickness (E101, E102, E104) determined to be able to receive a limited thickness of books and / or notebooks (81), which thickness is calculated to represent a determined maximum weight. Binder (1, la) according to any one of the preceding claims, characterized in that the envelope (10) includes one or more inner walls (15) which delimit  on the one hand, a so-called anterior compartment (101, 104) which is situated at the bottom of said envelope and adjacent to the back panel and the lower panel (12), and whose dimensions in width (L101, L104) and height (H101, H 104) are determined to accommodate one or more books or notebooks (81), and  on the other hand, one or more complementary compartments (103) located behind and / or above said at least one front compartment (101, 104) and having dimensions (H103, E103) determined so that none of them can accommodate a book or even a notebook. 12. Schoolbag (lb to le) according to any one of the preceding claims, characterized in that the at least one ventral holding belt (3) is formed in two half-belts (31, 32) joined at the belly. the carrier (9) by detachable fast-acting fastening means (33),  and in that each half-belt (31, 32) is further fixed, on the side of the ventral attachment (33), to the side strap (21, respectively 22) corresponding thereto. 13. Schoolbag (lb, ld, le) according to the preceding claim, characterized in that the side straps (21, 22) are fixed on the half-belts (31, respectively 32) by detachable fastening means fast maneuver ( 213, 223). 14. Satchel (le) according to any one of the preceding claims, characterized in that it further comprises an additional pocket (6) independent of the envelope (10) of said binder and which is fixed on the shoulder straps (21, 22) and / or the ventral holding belt (3, 31, 32) on the front of the carrier (9) by detachable fast-acting fastening means (61). 15. Schoolbag (lb to le) according to any one of claims 12 to 14, characterized in that the lower anchorage of the side straps (21, 22) is formed by the anchoring points (311 to 312, respectively 321 322) of the ventral holding belt (3, 31, 32).